THE BEGINNINGS OF LIFE. 243 



made their appearance. The difference between these 

 two forms is indeed quite trivial and unimportant, 

 and wholly unworthy, even from the old point of view, 

 of being regarded as a generic mark of distinction 1 . 



These observations of M. Pouchet have been confirmed 

 by MM. Joly and Musset, M. Pennetier and others. 

 The former observers declare 2 that they have watched 

 the evolution of specimens of Kolpoda cucullus in a pel- 

 licle that formed on water in which the contents of 

 a hen's egg were allowed to macerate. In this pellicle 

 there appeared, as they say, c en vertu d'une sorte de 

 cristallisation vitale/ the spherical masses of granules 

 constituting c les ceufs spontaneV'of Pouchet ; and these 

 in their turn, after a period in which the usual rotation 

 of the embryos within the egg membrane was observed, 

 gave origin to specimens of the organism above men- 

 tioned. On the removal of the first pellicle it was 

 succeeded by another in which similar developmental 

 phenomena were repeated. 



1 The actual disposition of the ciliae in different specimens of Infusoria 

 is subject to considerable variation. And yet many supposed species of 

 Oxytricba were distinguished from one another by Ehrenberg according 

 to the number and disposition of their ciliae, though M. Haime says 

 (' Ann. des Sc. Nat.' 1853, p. 117), ' la disposition de ces soies est sensible- 

 ment la meme dans les diverses especes du genre Oxytriche, ou du moins 

 dans les diverses formes d^crites comme telles.' Mr. Carter goes still 

 further. He says (' Ann. of Nat* Hist.' 1859, p. 249) that Haime's 

 Oxytricba, as well as Ehrenberg's O. pellionella, Kerona polyporum, and 

 Stylonichia silurus, are 'only states of the extremely variable Kerona 

 pustnlata.' 



2 See ' Compt. Rend.' (1860), t. li. p. 934. 



R 2 



